[beg the question] {v. phr.}, {literary} To accept as true something that is still being argued about, before it is proved true; avoid or not answer a question or problem. […]A Dictionary of American Idioms

[off the top of one's head] {adv.} or {adj. phr.}, {informal} Without thinking hard; quickly. * /Vin answered the teacher's question off the top of his head./ * /When Lorraine […]A Dictionary of American Idioms